Rebuilding front teeth that have worn excessively.

It seems safe enough to simply state that your front teeth are exposed to a greater level of force than they can withstand.

For whatever reason related to the physics involved, some of the forces get focused in a region of some of your crowns (hence they chip), others are absorbed by some crowns as a unit (hence they come off), and then some forces get directed to your teeth and their crowns as a unit (with the root evidently being the weakest link for at least one tooth, hence it has broken).

It's our back teeth that are supposed to bear the highest level of forces. People who don't have back teeth (your previous situation) subsequently shift their chewing activities forward. And as a result they often have problems like you describe because front teeth aren't intended to receive that level of force (constantly and regularly).

Possibly your replacement teeth in back aren't fully functional? (Possibly they don't come into full contact when you close together, hence you still chew with your front teeth? Or possibly the habit of chewing with your front teeth simply still exists?)

Or due to previous tooth shifting and wear (as a result of the loss of your back teeth), when your dentist rebuilt your mouth they "opened" your bite (made the height of your teeth closer to what they were originally) but by an amount that was too great, hence persistent forces are created (and evidently focused on your front teeth)?

Or possibly the excessive forces that exist are due to a habit of tooth clenching and grinding? (A very common scenario.)

For a start, evaluate what your current situation is. Your jaws have a normal "rest" position (teeth fully apart by a fraction of an inch) that they should be in almost all of the time (except when you are eating or at the end of a swallow).

If yours aren't, that's probably where the excessive forces that affect your front teeth come from. (This would be a common scenario with people who clench and grind their teeth.)

If you are at rest position 99% of the time, then the question is why when you eat is such a high level of force directed too your front teeth?

With the first case, you need to quit clenching, or else wear an appliance that can help distribute the forces your habit creates.

With the second case, unless it is the situation where an old habit of chewing with your front teeth simply persists (and can be corrected), your dentist will have to figure things out.

This link explains general reasons why crowns are placed (as opposed to fillings).
And this link provides additional information about the pros and cons of fillings vs. dental crowns.

But it's really only your dentist, after having examined your teeth, who has all of the information needed to help you decide between the two.

Then once your teeth have been rebuilt (and replaced in your case), you'll need to take steps to prevent future wear from occurring. It's very common for a dentist to have their patient wear a "night guard" appliance to help to prevent wear while they sleep. During the day you'll need to make a conscious effort not to grind your teeth so no more damage occurs.

We're guessing that due to the amount of wear your teeth have undergone your dentist feels that they need more available space/clearance in order to place upper front crowns.

This would have to do with where your upper and lower front teeth touch. When placing a crown, the tooth needs to be trimmed a certain amount to accommodate its thickness. We would think that your dentist feels that doing so might expose the nerve of your teeth, or else result in tooth nubs so short that the crowns wouldn't stay in place well.

As a solution a dentist will "open the patient's bite." They do this by making the back teeth taller (hence the crowns you mention) so there is more clearance available (front-tooth separation). That way the front teeth don't have to be trimmed so much to accommodate the crowns' thickness.

We get your longevity point. We would also mention that if a person's bruxism is not controlled that placing crowns may offer some benefits short-term but over the long-term will fail and/or cause problems (such as wear) with other teeth.

You seem motivated in your attempts to control your bruxism. And if you were 100% successful the concerns about future wear with or without crowns would be drastically reduced.

You don't mention how successful your efforts seem to have been over the last 10 years. If there are still some issues, have you considered including some daytime use of you guard to further reduce the level of wear that is occurring?

Only you and your dentist can make a decision about your treatment. If aesthetics aren't a big factor and further wear isn't occurring at a great rate, not placing crowns means less expense, less maintenance of restorations (crowns can come off, break, need replacement), usually it's easier to brush and floss natural teeth (thus reducing potential for gum disease), opening a person's bite can cause TMJ problems/issues, crowns that are not polished well can cause extensive wear of opposing teeth with bruxers, when heavy bruxing forces are involved porcelain crowns can break, crown wear can occur in bruxers. Ask your dentist but it seems naive to think that within the next 30 years of your life that this work wouldn't need serious maintenance or outright replacement.

Obviously this isn't an easy choice. Clearly everything depends on the level of bruxing activity that can be expected to continue. Good luck.